Next branch table for use with a branch predictor

摘要

A data processing system 2 is provided with branch prediction circuitry 20 for performing branch prediction operations. Next branch table circuitry 22 stores data identifying from a given branch instruction what will be the address of the next branch instruction to be encountered within the program flow. This next branch instruction address is supplied to the branch prediction circuitry 20 which uses it to form its prediction prior to that next branch instruction being identified as such by the instruction decoder 16. This permits branch prediction to commence earlier in the branch prediction circuitry 20 than would otherwise be the case.

主权项

1. Apparatus for processing data comprising:
instruction decoding circuitry configured to decode program instructions, each having an instruction address, to generate control signals for controlling data processing circuitry to perform data processing operations specified by said program instructions; branch prediction circuitry configured to perform a prediction of a branch outcome of a branch instruction in dependence upon at least an instruction address of said branch instruction; and next branch table circuitry configured to store data identifying for given instruction address in a computer program flow a next branch instruction address of a next branch instruction following said given instruction address within a current pass through said computer program flow; wherein said next branch table circuitry is configured to supply said next branch instruction address to said branch prediction circuitry before said instruction decoding circuitry identifies said next branch instruction as a branch instruction during said current pass; and said branch prediction circuitry is configured to use said next branch instruction address received from said next branch table circuitry to commence prediction of a next branch outcome of said next branch instruction before said instruction decoding circuitry decodes said next branch instruction during said current pass.